Refactor container build and installation pipeline to use configurable Makefile parameters (e.g. DISTROS, base images) and propagate them through all build, install, and test scripts

scripts/build/resolve-base-image.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+resolve_base_image() {
+  local distro="$1"
+
+  case "$distro" in
+    arch)   echo "$BASE_IMAGE_ARCH" ;;
+    debian) echo "$BASE_IMAGE_DEBIAN" ;;
+    ubuntu) echo "$BASE_IMAGE_UBUNTU" ;;
+    fedora) echo "$BASE_IMAGE_FEDORA" ;;
+    centos) echo "$BASE_IMAGE_CENTOS" ;;
+    *)
+      echo "ERROR: Unknown distro '$distro'" >&2
+      exit 1
+      ;;
+  esac
+}